Preplanning of Stereotactic Radiosurgery Using the Brainlab IPlan Treatment Planning System
K Ahn1*, N Ozturk1,2, B Smith1, B Aydogan1,2, (1) Univ Illinois at Chicago, Chicago, IL, (2) The University of Chicago, Chicago, ILSU-E-T-473 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: Frame-based stereotactic radiosurgery (SRS) requires fixation of an invasive head ring to ensure accurate targeting. Minimizing waiting time with head ring on is important for patient comfort and satisfaction. We report a practical preplanning solution for the Brainlab iPlan treatment planning system (TPS) that reduces waiting time by expediting the planning process on treatment day.
Methods: A water-filled anthropomorphic head phantom was used to acquire a surrogate CT image set for preplanning and fused with patient MRI image set which is usually available before the treatment day. Once an acceptable preplan was obtained, it was saved as a plan template and the phantom image set was removed from the Brainlab database to prevent any confusion and mix-up. On treatment day, patient CT was fused with MRI, customized beam settings from the preplan template were applied and optimized. Considerable reduction in treatment planning time was demonstrated by bench testing with both a conformal beam and a circular arc case.
Results: Preplans were generated in 20-25 minutes to satisfy <130% homogeneity, 100% coverage and <2.0 conformity index with the phantom CT. After applying the plan template and fine-tuning the pre-configured beam settings, treatment plans of comparable evaluation indices were obtained in 5 min and 1 min for the conformal and arc cases, respectively. This technique was successfully applied to our last 16 patient treatments.
Conclusion: The SRS preplanning technique implemented in this study for the Brainlab iPlan TPS offers an opportunity to thoroughly explore possible beam configurations, optimize planning parameters, resolve gantry angle clearance issues, and communicate and address challenges with physicians before treatment day. Preplanning has proven useful and time-saving in our clinic particularly for multiple-isocenter and dosimetrically challenging cases.